Multiple releasable interlocking mechanism for circuit breakers



E. A. PIFKE Oct. 30, 1951 MULTIPLE RELEASABLE INTEIRLOCKING MECHANISM FOR CIRCUIT BREAKERS 2 SHEETS-SHEET 1 Filed Oct. 7, 1950 Inventor Edgar Pi-FKe H is Atborn ey Oct. 30, 1951 MUL E. A. PlFKE 2,573,485 TIPLE RELEASABLE INTERLOCKING MECHANISM FOR CIRCUIT'BREAKERS Filed Oct. '7, 1950 2 SHEETSSHEET 2 28b Inventor EdgaT A. FifKe W b H is Attorney.

Patented Oct. 30, 1951 MULTIPLE RELEASABLllI INTERLOCKING MECHANISM FOR CIRCUIT BREAKERS Edgar A. Pifke, Philadelphia, Pa., assignor to General Electric Company, a corporation of New York Application October '7, 1950, Serial No. 189,013

7 Claims.

The invention relates to circuit breaker interlocking mechanisms and provides an improved. multiple releasable type of interlocking mechanism particularly suitable for interlocking two feeder breakers and one generator breaker so that either feeder breaker may be closed simultaneously with the generator breaker irrespective of which breaker may be initially closed but the two feeder breakers may never be simultaneously closed.

' However, the interlocking improvements of the present invention are applicable generally to provide each of a plurality of breakers with a plurality of interlock elements each movable for preventing closure thereof and selectively operated to prevent closure of each other breaker upon closure of any breaker, and having a common release mechanism for rendering predetermined interlock elements ineffective dependent upon which breaker is initially closed.

Hence one object is to provide each of a plurality of selectively operable breakers with a releasable interlocking mechanism f or insuring that when any breaker is initially closed a corresponding movable interlock element for each other breaker is automatically moved to prevent closure thereof.

Another object is to provide a releasing mechanism operable to release at least a predetermined one of the interlocking elements moved upon closure of any one breaker so as to permit closure of a corresponding other breaker simultaneously with the one breaker.

Another object is to insure at all times against simultaneous closure of predetermined breakers.

Another object is to provide three breakers in superimposed alignment with juxtaposed and jointly releasable interlocking mechanisms, each effective upon closure of the corresponding breaker for preventing closure of both other breakers and having a common release member operable for rendering each interlocking mechanism ineffective, so as 'to permit simultaneous closure of one other breaker.

Another object is to provide the interlocking mechanism for each breaker with a pair of relatively movable links having a latch for interconnecting the links for joint movement upon closure of the corresponding circuit breaker and with interlocking elements selectively carried on one or both of the relatively movable links for engaging the trip members of the other breakers to move these members to the tripping position so as to prevent closure of the corresponding breakers and to provide a common release member for releasing each latch so as to produce relative movement of one of each pair of links whereby an interlocked element carried thereby is rendered ineffective so that at least one of the trip members of the other breakers is returned to the non-tripping position and thereby permits closure of the corresponding other breaker.

Another object is to specially construct the genera-tor breaker interlocking mechanism so that both the interlock elements are carried on only one of the pair of relatively movable links whereby upon release of the latch therebetween, both of the trip members of. the feeder breakers are returned to the non-tripping position thereby en-.-

abling selective closure of either feeder breaker.

Another object is to specially construct each of the feeder breaker interlocking mechanisms so that each of the two interlock elements are care ried on a separate one of the relatively movable links so as to insure that when either feeder breaker is closed, the tripping member of the other feeder breaker is continuously held in the tripping position upon release of the latch while only the tripping member of the generator circuit breaker is returned to the non-tripping position to enable simultaneous closure thereof.

Further objects and advantages of the invention will appear in the following description of the accompanying drawings in which Fig. 1 is a side View of three latch trip type circuit breakers mounted in superimposed vertical alignment and provided with the improved multiple releasable interlocking mechanism of the present invention; Fig. 2 is an enlarged partial sectional view on the line 2-2 in Fig 1 looking in the direction of the arrows and revealing more clearly the detailed construction of the releasable latch structure interconnecting the relatively movable links of the multiple interlocking mechanism shown in Fig. 1; Fig. 3 is a side view of the releasable latch structure shown in Fig. 2; Fig. 4 is a sectional view along the line ll-B in Fig. 1 further showing the detailed construction of the biased multiple latch releasing member for the interlocking mechanism; and Fig. 5 is a schematic exploded perspective view showing more clearly the cooperating relationships of all the various parts of the improved multiple releasable interlocking mechanism of the present invention.

As shown in Fig. 1, the pair of feeder breakers FI and F2 are mounted in superimposed vertical alignment with the generator breaker GI These breakers are shown as of the improved trip free latch type more fully described and claimed in application Serial No. 775,573, filed September 23, 1947, now Patent No. 2,549,441, April 17, 1951, by J. A. Favre and assigned to the assignee of the present invention, and are provided with the rotatable closing handles l abc and the manual tripping buttons Za -b e. The electromagnetic and manual operating mechanisms for the breakers together with their circuit interrupting contacts are housed within the molded enclosing casings 3a-bc that are secured to the supporting frame (i. For interlocking purposes the breaker operating members 5a-b-c have the ends thereof extended outside of the casings 3abc and each is movable in the direction indicated by the arrow upon closure of the breakarm 9 so as to engage the movable switch contact ll! with the stationary switch contact ll when the operating member a is moved in the direction indicated by the arrow. With the trip shaft 6a in its non-tripping position as shown, movement of the operating member 5a in the direction indicated by the arrow may be accomplished either electromagnetically or by rotation of handle la through the agency of suitable tripfree type latched toggle mechanism (not shown) and the switch contacts are held in the closed position under the control of the trip shaft 6a so that counterclockwise rotation of paddle la will trip the latched toggle mechanism to open the breaker as more fully described in the above noted Favre application. However closure of the breaker Fl is eifectively prevented as long as the trip shaft 6a is held in the tripping position since this renders the latched toggle mechanism totally ineffective to move the operating member 5a in the direction to close the breaker. Each of the other circuit breakers F2 and GI is constructed to operate in the same way.

The improved multiple releasable interlocking mechanism of the present invention is mounted on the frame 4 by means of the three brackets 'l2abc, each pivotally supporting a corresponding one of the bell cranks l3a b-c by means of the corresponding pivot pin l4a--bc. These bell cranks are each provided with a suitable elongated slot l5a-b--c for operatively engaging with the respective circuit breaker operating members 5a'bc. The opposite ends of the bell cranks are operatively connected respectively by the pins l'la-bc respectively with a corresponding one of the links [8a, l9a. and 20b of the three separately operable interlocking mechanisms l8, l9, and'20 as indicated in Fig. 5. Each of the pins l'la-b-c passes through suitable elongated slots in the adjacent links so as to maintain the three interlocking mechanisms in compact juxtaposition and in closely adjacent operating relation with the vertically aligned operating members 5a.bc and tripping paddles 'lab--c of the circuit breakers.

As indicated in Figs. 2 and 5 each interlocking mechanism is provided with pair of relatively movable overlapping links l9a and b, l8a. and b and 20a and b. Each of the links l8a, I90. and 20a has pivotally mounted thereon a corresponding one of the latches 2 la-bc and each latch is biased by springs 23a, b and 0 connected to the brackets 240,, b and 0 carried by the corresponding link so as to engage with one of the pins 25a,'b-c carried on the corresponding relatively movable link so as to interconnect each pair of relatively movable links for joint movement. The pivot pins 26 for the latches 2labc as well as the guide pins 21 extend through suitable slots formed in the links lBb,

- lfi b and 201) so as to maintain each pair of relatively movable links in juxtaposed alignment. As. shown in Fig. 5 the link l8b is biased for relative movement with respect to link l8a by the tension spring 28a and the tension spring 28b similarly biases link l9b for relative movement with respect to link lSa. A compression spring 280 serves to bias link 20a for relative movement with respect to link 20b. Thussuch relative movements will occur after a joint movement of .each pair of ,links upon release of the latch interconnecting the pair of links for joint movement.

The latch releasing mechanism as shown in detail in Fig. 4 is provided with an operating rod 30 slidably mounted in the channel member 3| that is carried by the brace 32 secured to the frame 4. The yoke 33 is fixedly secured to one end of the operating rod 30 and carries the cross bar 34 for engaging with each of the latches 2labc when the rod 30 is moved longitudinally against the bias of the spring 35 by pulling on the handle 36 secured to the outer end of the rod 30. The adjustable stop 31 serves to limit the releasing movement.

As shown in Fig. 5, a pair of interlock elements are provided for operating each trip paddl of each breaker. Thus the trip paddle la, of the feeder breaker Fl may be operated to the tripping position to prevent closure of the breaker by operation of either of the interlock element 46 carried by the link I901. or by separate operation of the interlock element 4l carried by the link 2001.. Similarly trip paddle lb of circuit breaker F2 may be operated to prevent closure thereof either by the interlock element 42 carried by link l8a or the interlock element 43 carried by the link Zlia. Likewise trip paddle Tc of the generator breaker Gl may be operated to prevent closure thereof either by the interlock element 44 carried by the link l9b or the interlock element 45 carried by the link l8b.

Interlocking operation As shown in Fig. 5 all of the interlocking parts are in their respective positions that permits selective operation of any one of the three circuit breakers from the open position to the closed position. Assuming that the generator breaker Gl is initially closed, the operation of the circuit breaker operating member 5c in the direction indicated by the arrow will rotate the bell crank I30 and thereby raise the pin l'lc so as to jointly move the pair of links 20a and 20b upwardly and thereby carry the interlock elements 4| and 43 to move the trip paddles la and lb to the trip position and thereby effectively prevent closure of either of the feeder breakers Fl, F2.

When the release handle 36 is pulled, the operating rod 30 is moved against the bias of spring 35 to carry the bar 34 into engagement with the latch 2lc and thereby disengage the latch2lc from the pin 250. As a result spring 280 will move the link 25a downwardly, thereby disengaging interlock elements 4! and 43 fromrthe trip paddles la and lb respectively. This enables either of the feeder breakers Fl, F2 to be selectively closed.

Upon the closure of feeder breaker Fl while the handle 35 is maintained in the release position, operating member 5a will be moved in the direction of the arrow to rotate the bell crank .l3a and thereby raise the pin lla to move the link l8a in the upper direction. Since the release handle 36 is maintained in the releasing position bar 34 will effect the release of the latches 2la and 2 lb simultaneously with the release of latch Zlc and the link [8b will not be raised jointly with the link l8a. Consequently, only the interlock element 42 is elfective to raise the trip paddle lb and thereby prevent closure of the other feeder breaker F2. After the generator breaker GI and the feeder breaker Fl are closed simultaneously as just described, the release handle 36 may be released so that the bar 35 is carried out of releasing relation with the iatches Zlc, Zia and 2 lb.

In case the feeder breaker F2 is selected for closure instead of the feeder breaker Fl while the handle is maintained in the release position, then operating member 52) would be moved in the direction of the arrow to rotate the bell crank l3b so as to raise the pin Nb and thereby move the link ltd in the upper direction. However, with the bar 3 3 maintained in releasing engagement with the latches, latch 2th will be released so that bar itb will not be moved jointly with the bar 59a. As a result only the interlock element 45 will be effective to move the trip paddle la and thereby effectively prevent the closure of the other feeder breaker Fl while the feeder breaker F2 is closed simultaneously with the closure of the generator breaker GI.

With all the breakers in the open position, if the feeder breaker F! is selected for initial closure, then both of the links lilo and 58b will be moved jointly upon rotation of the bell crank I3a by movement of the operating member 5a in the direction indicated by the arrow to raise the pin Ila. In this case both the interlock element 42 and the interlock element 45 Will engage respectively with the trip pedals lb and to thereby efifectively preventing closure or the feeder breaker F2 and the generator breaker GI until the release handle its is pulled to move the bar 34 into releasing engagement with the latch Zla to enable closure of the generator breaker GI.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A selectively operable triple circuit breaker interlocking mechanism having in combination a pair of interlock elements for each breaker, each separately operable for preventing closure of the corresponding breaker, a corresponding operating member movable upon closure of each breaker and provided with means including a releasable latch for jointly operating the corresponding interlock element of both other breakers to pre vent closure thereof and means including a member movable for separately releasing the latch of each operating member to render an interlock element operated thereby ineffective.

2. A selectively operable multiple circuit breaker interlocking mechanism having in combination a plurality of interlock elements for each breaker, each separately operable for preventing closure of the corresponding breaker, a separate operating member movable upon closure of each breaker and provided with means including a releasable latch for jointly operating a corresponding interlock element of each other breaker to prevent closure thereof, and means including a release member movable for separately releasing the latch of each operating member to render an interlock element operated thereby ineifective.

3. An interlocking mechanism for a plurality of selectively operable circuit breakers having in combination a separate pair of relatively movable links for each breaker provided with means for effecting joint movement thereof upon closure of the corresponding breaker and having interlocking element operated thereby for preventing closure of each other breakers and means including a member independently operable for effecting relative movement of one link of each pair to render an interlock element operated thereby ineffective.

4. An interlocking mechanism for a plurality of selectively operable circuit breakers having in combination a separate pair of relatively movable links for each breaker provided with means including releasable interconnecting means for effecting joint movement thereof upon closure of the corresponding breaker and having interlock elements carried thereby for preventing closure of each other breakers, and means including a member movable for releasing the interconnecting means of each pair of links to render an interlock element carried by one of the links ineffective.

5. In combination, a plurality of selectively operable circuit breakers each having a separate trip member operable to prevent closure thereof, a separate pair of relatively movable links for each breaker provided with means for effecting joint movement thereof upon closure of the corresponding breaker and having interlock elements carried thereby for engaging the trip members of the other breakers to prevent closure thereof and means including a movable member for effecting relative movement of one of each pair of links to render an interlock element carried thereby inefiective.

6. A multiple circuit breaker interlocking mechanism having in combination a plurality of pairs of relatively movable links each provided with releasable means for interconnecting the pair of members for joint movement, an operating connection extending between one of the members of each pair and a corresponding circult breaker for effecting joint movement of the members upon closure of the breaker, interlocking means carried by the other member of each pair for preventing closure of another circuit breaker upon joint movement of the pair of members, and means including a member movable for releasing the interconnecting means of each pair of members to render the interlocking means carried by the other member thereof ineffective.

7. A multiple aligned circuit breaker interlocking mechanism having in combination a plurality of juxtaposed pairs of relatively movable overlapping links having aligned releasable latches biased to interconnect each pair of links for joint movement, a pivoted operating connection extending between one of the links of each pair and a corresponding circuit breaker for efiecting joint movement of the links upon closure of the breaker, interlocking means carried by the other link of each pair for preventing closure of at least one other circuit breaker upon joint movement of the pair of links, and means including a biased member mounted for movement against its bias into releasing engagement with the latch of each pair of links to operate said latch against its bias and thereby render the interlocking means carried by the other link ineffective.

EDGAR A. PIFKE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,251,294 Scott Dec. 25, 1917 2,531,157 Pifke Nov. 21, 1950 

